Identification of volatile compounds in soybean at various developmental stages using solid phase microextraction

Soybean (Glycine max) seed volatiles were analyzed using a solid phase microextraction (SPME) method combined with gas chromatography-mass spectrometry (GC-MS). Thirty volatile compounds already reported for soybean were recovered, and an additional 19 compounds not previously reported were identified or tentatively identified. The SPME method was utilized to compare the volatile profile of soybean seed at three distinct stages of development. Most of the newly reported compounds in soybean seed were aldehydes and ketones. During early periods of development at maturity stage R6, several volatiles were present at relatively high concentrations, including 3-hexanone, (E)-2-hexenal, 1-hexanol, and 3-octanone. At maturity stage R7 and R8, decreased amounts of 3-hexanone, (E)-2-hexenal, 1-hexanol, and 3-octanone were observed. At maturity stage R8 hexanal, (E)-2-heptenal, (E)-2-octenal, ethanol, 1-hexanol, and 1-octen-3-ol were detected at relatively high concentrations. SPME offers the ability to differentiate between the three soybean developmental stages that yield both fundamental and practical information.     

Biological control of decay in Douglas Fir poles — seven years perspective

Ten, creosote treated, Douglas-fir poles infected with Poria carbonica at the ground line zone were inoculated artificially with Scytalidium sp. FY strain in January 1967. FY became established in the poles. One pole was set aside for comprehensive sampling and thirty-six samples were taken from the ground line zone of it seven years later (January 1974). One sample yielded live FY, 2 samples yielded bacteria, 9 samples showed scanty fungal growth and 24 samples yielded no microorganisms. None of the 36 samples showed advanced decay or Poria carbonica. These observations are consistent with the mechanical condition of the wood in the other 9 poles inoculated with FY after decay had begun.     

Characteristics of lignin obtained from steam-exploded softwood with soda/anthraquinone pulping

Lignins were obtained from a mixture of softwood sawdust using a hydrolytic pretreatment and a subsequent soda-anthraquinone delignification/pulping stage. Their potential uses and the effect of the pretreatment conditions on the yield (% of recovered lignin from black liquors) and chemical composition of isolated lignins were evaluated. The severity factor used combined the temperature and time of the hydrolytic process in a single ordinate (R_o). The severity range was modified from log R_o = 2.6 to log R_o = 4.6 and the pulping conditions were constant throughout the experiments. The effect of the cooking time on the chemical composition of precipitated lignins was also studied between 135–170 min for original (non-pretreated) material. Yield, elemental analysis, molecular weight distribution, Fourier transform infrared spectra (FTIR), structure, and the methoxyl and aliphatic/aromatic alcohol content of the various lignins, were compared.     

Comparison of Models for Olfactometer Data

Olfactometer experiments are used to study the responses of arthropods to potential attractants, for purposes such as understanding natural defenses of plants against their herbivores. Such experiments typically lead to multivariate data consisting of small correlated counts, which are overdispersed relative to standard models. In this paper models that account for the overdispersion under different hypotheses on insect behavior are described and illustrated with an example, and a graphical approach to discriminating among them is briefly discussed.     

Analysis, assessment, and improvement of fertilizer distribution in pressure irrigation systems

The transformation of traditional irrigation systems into pressure irrigation networks allows water users associations to use central fertigation systems. For efficient fertigation management, however, it is essential to obtain uniform distribution of the injected fertilizer through the system and to understand the hydraulic processes that take place in the central fertigation system. This will allow users to implement strategies that improve fertilizer distribution. In this work we develop a new methodology to improve fertilizer distribution uniformity and apply it to a case study. The results show how fertilizer distribution can be improved by means of proper scheduling of irrigation deliveries. The best results are obtained when fertigating sectors operate without non-fertigating sectors and there are not intermediate irrigations without fertilizer, achieving an improvement of the fertilizer distribution of 10.5%. In addition, this work highlights the difficulties of obtaining uniform distribution of fertilizer in a centralized irrigation system when there are users that do not want to make use of it.     

Effect of soybean lipoxygenase on volatile generation and inhibition of Aspergillus flavus mycelial growth

Volatiles generated from lipoxygenase (LOX) normal and LOX deficient soybean (Glycine max) varieties with and without added lipase inhibited Aspergillus flavus mycelial growth and aflatoxin production. Soybean volatiles were analyzed using a solid phase microextraction (SPME) method combined with gas chromatography-mass spectrometry (GC-MS). Twenty-one compounds, including 11 aldehydes, three alcohols, four ketones, one furan, one alkane, and one alkene were detected in the LOX normal soybean line. However, only nine volatile compounds were observed in the LOX deficient soybean variety. The antifungal aldehydes hexanal and (E)-2-hexenal were observed in both LOX normal and LOX deficient lines and were detected at significantly higher amounts in soybean homogenate with added lipase. These aldehydes may be formed through alternate pathways, other than the LOX pathway, and may account for the inhibition of A. flavus growth observed. Other volatiles detected, particularly the ketones and alcohols, may contribute to the antifungal activity observed in both LOX normal and LOX deficient soybean lines. These results suggest that other factors, other than LOX activity, may better explain why soybeans are generally not as severely affected by A. flavus and aflatoxin contamination as other oilseed crops.     

Induction of the soybean phytoalexins coumestrol and glyceollin by Aspergillus

Several isoflavonoid phytoalexins produced by soybeans are known to be estrogenic, with potential beneficial health effects in humans. Increased production of phytoalexins by the soybean plant will facilitate research efforts in this area. In this study, phytoalexin induction and accumulation in soybean cotyledon tissue was observed using four species of Aspergillus: A. sojae, A. oryzae, A. niger, and A. flavus. All four Aspergillus species tested elicited phytoalexin accumulation in living soybean cotyledons. Results from a time course study indicated that maximum concentrations of the phytoalexin glyceollin, 955 microg/g fresh weight (fw), occurred at day 3 in soybean cotyledon tissue inoculated with A. sojae. Other Aspergillus species caused an accumulation of glyceollin at significantly lower levels. A maximum concentration of coumestrol of 27.2 microg/g fw was obtained from soybean cotyledons inoculated with A. niger. Soybean phytoalexins induced by food-grade A. sojae and A. oryzae allowed the collection of higher concentrations of phytoalexins for further examination in several in vitro and in vivo biological studies conducted to determine potential estrogenic activities.     

Cloning of fox (Vulpes vulpes) Il2, Il6, Il10 and IFNgamma and analysis of their expression by quantitative RT-PCR in fox PBMC after in vitro stimulation by Concanavalin A

The immune response in the fox (Vulpes vulpes), despite the success of the oral rabies vaccine is not well characterised, and specific immunological tools are needed. A quantitative RT-PCR using SyBR Green to investigate fox cytokine expression after antigen PBMC in vitro re-stimulation is presented here. First, we cloned by homology with dog cytokine sequences the fox IL2, IL6, IL10, IFNγ and a partial 18S sequence. Fox specific primers were then defined and used to set up a species-specific quantitative RT-PCR assay using SyBR Green and 18S housekeeping gene as internal standard. The technique was validated using total RNA from fox PBMC stimulated with a polyclonal activator, Concanavaline A.